Functions of the skin microbiota in health and disease

Abstract

The skin, the human body’s largest organ, is home to a diverse and complex variety of innate and adaptive immune functions. Despite this potent immune system present at the cutaneous barrier, the skin encourages colonization by microorganisms. Characterization these microbial communities has enhanced our knowledge of the ecology of organisms present in normal skin; furthermore, studies have begun to bring to light the intimate relationships shared between host and resident microbes. In particular, it is apparent that just as host immunological factors and behaviors shape the composition of these communities, microbes present on the skin greatly impact the functions of human immunity. Thus, today the skin immune system should be considered a collective mixture of elements from the host and microbes acting in a mutualistic relationship. In this article we will review recent findings of the interactions of skin microbial communities with host immunity, and discuss the role that dysbiosis of these communities plays in diseases of the skin.

Indigenous Bacteria and Fungi Drive Traditional Kimoto Sake Fermentations

“…The role of bacilli in sake flavor development is unknown, but they can produce an array of ketones, acids, esters, and other compounds important to soybean fermentations (39) and may play a similar role here. Staphylococcus is frequently detected on human skin (40) and in food fermentations, including other Asian beverage fermentations that employ semisolid stages similar to koji preparation (34)(35)(36)(37). The common pattern observed in rice fermentations of early dominance by Staphylococcus and Bacillus species succeeded by lactic acid bacteria has led other authors to speculate that these bacteria may produce growth factors conducive to lactic acid bacteria growth later during the fermentation (38), but this relationship has yet to be demonstrated.…”

The Role of Cutaneous Microbiota Harmony in Maintaining a Functional Skin Barrier

“…The majority of these micro-organisms are harmless or beneficial, providing protection against pathogens and playing an important role in modulating the host's cutaneous innate and adaptive immune systems (1) . The skin is constantly exposed to factors (e.g., ultraviolet radiation, pollution, topical medications, skin care products) that can alter the balanced relationship between the skin and its microbiome (2) . Such disruption may result in increased risk for infections, chronic inflammatory skin disease (e.g., atopic dermatitis, psoriasis, rosacea, acne), and complaints of sensitive, pruritic, and irritated skin (3) .…”

“…These bacteria contribute to protection against pathogen growth by competing for nutrients and space (2) . Some bacteria directly restrict the growth of competitors via production of antimicrobial compounds that can inhibit reproduction of closely related species without affecting the organisms producing them (2) .…”

Short-Term Exposure to Coal Combustion Waste Has Little Impact on the Skin Microbiome of Adult Spring Peepers (Pseudacris crucifer)

“…Our knowledge in this area is growing in large part because of advances in molecular microbiology and next-generation sequencing technologies that now allow us to study these complex microbial communities without culturing them. Studies performed by the Human Microbiome Project indicate complex interactions in these symbiotic microbial communities that influence their function (2), and disturbance and dysbiosis in these communities contribute to a variety of disease states (3,4).Most studies that examine the perturbation of symbiotic microbial communities in vertebrates have thus far focused on the impacts of antibiotics in humans and model lab systems (5-9). There are relatively few studies that examine the role of environmental contaminants on the human microbiome or in model systems (10-12) and even fewer that address this in wildlife.…”

“…Our knowledge in this area is growing in large part because of advances in molecular microbiology and next-generation sequencing technologies that now allow us to study these complex microbial communities without culturing them. Studies performed by the Human Microbiome Project indicate complex interactions in these symbiotic microbial communities that influence their function (2), and disturbance and dysbiosis in these communities contribute to a variety of disease states (3,4).…”